Hi everyone!
I downloaded Myst of Pandaria - not the old version, the New one - and started WoW.exe, but it gives me a fatal error with some infos and this:
"Failed to open required archive Data/enGB/wow-update-enGB-17345.MPQ with error : 5"
use the torrent again and select for download only the file "wow-update-enGB-17345.MPQ", however in your case I would delete the client and get the MoP Old from https://www.warmane.com/download, anytime people get the "new" version someone come here to complain about something... ( the new version has the WoD model, that is the only difference)